1291-P: Characterization of Gut Microbiota in Lean Type 1 Diabetes, Overweight Type 1 Diabetes, and Healthy Controls

Background: The incidence of type 1 diabetes (T1D) and overweight/obesity is on the rise. Previous studies showed altered gut microbiota in children with T1D where gut microbial differences between obese and lean children without diabetes were reported. The purpose of the study was to characterize the microbial composition of lean and overweight children with T1D at disease onset in comparison to healthy controls. Methods: We enrolled 26 children with T1D at disease onset including 15 lean and 11 overweight T1D and compared them with age, gender and BMI matched 14 lean and 8 overweight controls. Stool swabs were collected and DNA extraction was performed using Qiagen DNA mini kit. Bacterial regions v3, v4 were amplified using 16s primers. Amplicons were cleaned, barcoded, size selected and sequencing was completed on Ion Torrent S5 sequencer. Results: The four most abundant phyla in both groups were Proteobacteria, Firmicutes, Bacteroidetes and Actinobacteria. At the genus level, noted significant increase in pro-inflammatory microbes such as Serratia in T1D compared to controls without diabetes (P value= 0.047). Overweight T1D had marked decrease in the beneficial genus Lactobacillus compared to overweight controls. Similar observation was reported when lean T1D was compared to matched lean controls. Although not significant, anti-inflammatory genera like Clostridium had lower relative abundance in obese T1D compared to their lean counterparts. At the species level, when overweight T1D were compared to their matched controls, there was a marked reduction in L. brevis and L. Zeae known for their anti-inflammatory effects (P value = 0.038, 0.046 respectively). Conclusion: Our study showed alterations in the gut microbiome in children with T1D with significant increase in pro-inflammatory microbes. Additionally, being overweight negatively impacted the microbiome. Disclosure S.B. Gowda: None. R.M. Farrell: Research Support; Self; TODAY study. Stock/Shareholder; Self; Dexcom, Inc., Tandem Diabetes Care. S.A. MacLeish: None. I. Salem: None. M.A. Retuerto: None. M.A. Ghannoum: None.